The big news this week is the coming Evolang conference in Utrecht, but there is also an important new review article on “Social Cognition and the Evolution of language” by Tecumseh Fitch (who will be in Utrecht celebrating his new text book), Ludwig Huber, and Thomas Bugnyar in the latest Neuron journal. The three authors have just created a Department of Cognitive Biology at the University of Vienna, and with this paper they are off to a fine start. Their primary thesis—“human language and social cognition are closely linked”—will be familiar to anyone who reads this blog, but they provide much comparative biological data for their claim.
The material that made me sit up was a discussion of ravens and their ability to “recruit” other ravens in feasting on carcasses. The author’s note that Derek Bickerton asserts boldly in his recent book, Adam’s Tongue that “recruitment was … the selective pressure that started protolanguage” [quoted on p. 806]. The authors then proceed to call this idea into question by showing how ravens recruit fellows.
In this case, we can consider two types of ravens: territorial ones that breed, and non-territorial ones that do not breed. The non-territorial ones are readily chased off of carcasses by ravens who claim the territory. To change the balance of power in these struggles non-territorial ravens recruit fellow non-territorials and as a group they can hold their own on the carcass.
When such a raven finds a carcass it makes a call that may alert any other ravens in the area. It feeds as it can and at night flies off to a roost where it is joined by other non-territorials. The next morning the raven and co-roosters fly off together to the carcass. The raven has recruited other ravens to join it. How they recruit their fellows is not yet understood, but presumably it is not by saying, “Psst, I’ve got a dead one.”
Bickerton’s primary argument about the start of language is that it allowed individuals to refer an absent carcass and recruit others to come join in on the feeding. The raven illustration does not disprove Bickerton, but it certainly shows that you don’t need language either for recruiting or “displacement” (passing information about something absent).
I think I have said before that language seems unlikely to have started as the solution to any one problem. Evolution can handle any single task with a more focused adaptation. There seems no reason to doubt that early Homo did use proto-speech for referring to absent things and for recruiting, but there also seems no reason to suppose it was limited to that role. In fairness to Bickerton, his theory is much richer than a simple displacement/recruitment did it ,but he does specify those details.
Another lesson here is that we have to be very careful about scenarios that are based on any single feature said to be exclusive to language. All it takes is one field biologist to say, hey, I’ve seen an animal do that, and the theory suffers. It seems a bit of a needless, self-inflicted wound, rather like religious folk who base their defense of religion on this or that so-far unexplained evolutionary detail. What is needed to explain the uniqueness of language is more than a unique trait. We have to identify some unique essence, so that as this or that trait turns up in the biological world, the definition of language stands unscarred. On this blog I have from time to time proposed that language is a kind of communal perception by other means. You may have some other definition, but really, no study of language is going to get at its depth and power by saying that what makes it different from other animal signals is displacement, or recursive syntax, or what you will.
FoxP2’s Role in Vocal Learning
One of the real surprises I’ve had working on this blog has come from the reports that very remote species have something to teach us about language. When I was first starting this blog a woman asked me if I planned to say much about birdsong. I said no because they were so remotely related to us that I couldn’t expect to learn from the. Pardon, madam, I was wrong.
At least I was not alone. The authors of the review article write:
[Given the difference between bird and human brains, and the difference between bird and human vocal systems] it was quite surprising to find that the same gene [FoxP2] plays a causal role in [the vocal learning] of these species. This appears to be another example of “deep homology” in which the development of convergent structure is mediated by homologous genes. [808]
Apparently, besides contributing to vocal learning in humans, it seems to have, at three separate evolutionary points, contributed to vocal learning in hummingbirds, parrots, and songbirds. Another group in which vocal learning and FoxP2 are combined is in bats. (Elsewhere in the paper the authors mention complex vocal learning in cetaceans and seals [807] but perhaps their genome is not yet properly studied to say if they manage with or without an altered FoxP2.)
It would be interesting to see if any of these animals took their vocal learning a step further and have a real language. I don’t expect it, but at least we know the most promising places to look.
Shared Gaze
Early in the paper the authors discuss how interest in where another is looking “undergirds word learning via joint attention” and its various stages of development [707]. The stages proposed are:
- Awareness that one is being looked at. This ability is said to be widespread, “presumably because of [its] relevance to social or antipredator behavior. [797]
- Following another’s gaze direction. This relatively common social “orientation response” allows one individual to discover what others are looking at. Ravens can even move to another location so that they can see what has caught another’s eye. (For example, something behind a fence.)
- Identifying another’s target of attention. This ability goes beyond looking where another is looking to grasping why the other is looking there when simple perception is not enough. Apes are not very good at using gaze to find hidden food, for example. Dogs, on the other hand, are “outstanding” at determining the reason of such attention. The authors do not say how talented wolves are at the task.
All in all the paper makes for provocative reading, and since it is online for free I urge you to check it out.
Stay tuned to this blog this week as news comes in from Utrecht.
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